| 摘要 |
PROBLEM TO BE SOLVED: To provide a back-filling method for an underground excavated hole, which enables the back-filling of the excavated hole, reaching a confined aquifer, by preventing a back-filled section of an impermeable layer from being destroyed by swell. SOLUTION: So as to back-fill the impermeable layer 3 sandwiched between an aquifer 2 near a ground surface and the confined aquifer 4 through which confined water flows, the excavated hole H is filled with dried impervious granular matter with water-absorption expansibility, such as granular bentonite B. River sand S and the like are infilled under an impervious layer 23 which is formed by back-filling the impermeable layer 3 with the granular bentonite B, so as to form a confined permeable layer 24. A permeable material such as the river sand S is accumulated on the impervious layer 23, so as to form a permeable layer 22. COPYRIGHT: (C)2008,JPO&INPIT
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